The remains of a woman found Monday morning in a pond in St. Johns have been positively identified as that of Twila Joyner, an 85-year-old woman who went missing from her nearby Pitch Pine Avenue home Sunday, according to the St. Johns County Sheriff’s Office.

An autopsy revealed the cause of death was accidental drowning with a contributing factor of Alzheimer’s disease, the Sheriff’s Office said.

Joyner was last seen going to bed about 7 p.m. Saturday, then was reported missing by her family. Her body was found just after 10 a.m. Monday in a retention pond near her Northwest St. Johns County home after a two-day search by officers from St. Johns, Putnam County and Jacksonville.